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Description

The PSDR is a completely stand-alone (no computer needed), compact, Portable Software Defined Transceiver (hence the name, sorta). Originally designed for backpacking use by Ham Radio operators. It includes complete coverage up to about 30Mhz (plus 144Mhz), it has a 168Mhz ARM processor, color display, and an innovative interface.

The entire design is Open Source. The electronics are designed and laid out to be easy to understand and tinker with. In addition to source code, schematics, board layout and parts lists, articles and videos describing the theory of the design are being created.

License Information: The project code is still very much in development. It currently uses the Adafruit GFX and ILI9340 libraries (both being adapted for this application) and is likely to use other libraries in the future. I will comply with any licenses for libraries I include, and plan to license the project itself under a permissive license (like MIT) or a copyleft license like GPL. I would very much appreciate suggests on this.

About the PSDR1: There were a lot of subcircuits that I had never tested for this project (and were hard to breadboard at the frequencies and sizes involved) so I built the PSDR1 board you see here to demonstrate all those parts. I left off the easy stuff (like a battery charger, the whole GPS sub system) and a few of the more advanced parts (like the RF switching, and phase and amplitude measurement IC) Also, while the LCD module was expedient, the next version will have it integrated directly.

Project Logs

So I get home yesterday to find an unexpected package. Inside is a Ham Radio magazine (The December 2014 issue of Funk Amateur, I like the name!) with a note.... all in German. Sweet! I flip through it and to my shock, I find the PSDR! WHAAAAT!? What a cool thing! (I'd scan the whole thing, but that might be verboten, copyright stuff, you know.) I googled to see if the article was online, didn't find it, but did find a mention of the PortableSDR here.

The Kickstarter campaign is off to a great start! Last I looked it was almost to $12,000 (20% of the goal) at this rate it will be successful! Thank you so much everyone for your support!

I am getting a lot of messages, and I am trying to get caught up on posts and things, I hope to get caught up soon.

I just wanted to make a quick post here to let you know that I am still here. I wanted to have the Kickstarter live by now, but I really need to get some quotes back on PCB manufacturing, or I wont be able to set the prices with any confidence. I am so excited to get these out into the world, but I don't want to go broke doing it, you know?

I have an initial quote on the metals (though I want to change the design a little bit) and have been meeting with a local PCB assembly house. I've worked with them (as well as many others) for other projects and have found their work to be absolutely amazing. They cost a little more, but I think it will be worth it in boards that will work well for a long time. Also, since they're local, I won't have to pay for shipping, wait for shipping, or, for example, fly to China (I'm dying to go, but not on my own dime, you see).

I hope to have a quote back from them soon. When I've got everything figured out, you'll be the first to know!

Hi everyone! I got 3rd place! I'm the 3rd best hacker in the world! Thanks everyone for your support! Congratulations to the other finalists, in particular SatNOGS! I have an unused, wooden garage that would be perfect for housing one of their antennas trackers. I'll need to get on that. Also, I would love a tricorder and spectrometer. I'd like a chipwhisperer too, but I think it's a little over my head.

So where have I been? (Sorry about that, btw) Well first, after all the stress of the contest, it was nice to kinda do nothing for a while. But mostly I've been trying to figure out how to get the PSDR produced so you can have one!

I've poured over the survey data; very interesting stuff! There are a few things in there that are encouraging; so many people said they'd buy a PSDR2 AND a future version! There are also a few things that people aren't going to like. Maybe it was the BaoFeng comparison, but a pretty large number of people said it would only be worth say $50-150 to them (some even less!). There's no way that can happen, it's made of expensive parts and.... how can I compete with a big Chinese company!

Right now I am finding places that can do the manufacturing for me, particularly the metal housings and PCB assembly. When I have some quotes back, I'll be able to determine what I can charge and not go broke (a very real possibility if I'm not careful).

I hope to have a Kickstarter project up in about a week. Thanks for your patience everyone! I haven't forgotten about you!

Today, in the interview post about the RamanPi, Brian says, "If you're wondering who the winner of The Hackaday Prize is, even I don't know. [Mike] and a few Hackaday overlords do," Thinking of it now, of course the results would be known before the announcement, but it hadn't really occurred to me until I read that. For some reason it seemed weird to me. Whether I have won first place or not is known, but not to me. So in a weird way, I am in the superposition of both having taken first, and not. That is, until Thursday morning (for me 5 am :/ ) when the wave function will collapse. I think it would be fun to be in their position, to know that you were about to change someone's life, and you knew it, but they didn't. Good luck to my fellow finalists! No matter the outcome, I'm happy to have made it so far.

Pictured above is Girl Kitty, she's been our cat since I was a teenager (which makes her about 18 years old) but, unlike Schrödinger's cat, Girl Kitty is, thankfully, alive.

In other news, the response to the survey has been MIND BLOWING! The PSDR has about 650 followers, not everyone is going to respond, I guess I expected about 100 responses. Right now I have 1,106! (Which is, by the way, probably enough) THANKS EVERYBODY! It's been amazing to see such an overwhelmingly positive response! I'm still going through the data and want to devote a proper post to it. Give me a few days. I'm really learning a lot by going through all of this.

I shot this before the Final Overview Video, but didn't get around to posting it. Basically, it shows that my first attempt at an amplifier board for the PSDR2 was unsuccessful, also, I need filtering. I think that what I showed in the video might not have been that meaningful because I had already damaged the amp at that point. Nevertheless, it seems that filtering before the amplifier is going to be required. I have a circuit I want to try that would be a digitally variable low-pass filter. I think it will work, just not sure if will work at RF frequencies.

I was also lucky to bump into a pretty seasoned RF engineer and picked his brain about designing this amplifier (I only picked the surface though, since I could only take about 5 minutes of his time) basically, it sounds like MMICs will probably only get me to 1 W. Which is not terrible. Beyond that, I'll probably have to design a discrete circuit. BUT he also suggested a trick I'd read about, where you use a power splitter, then, say, 5 MMIC amps, then a combiner, and there you go. I'm interested in trying that. That would also make it easy to step down power, and even provide some redundancy...

THANK YOU SO MUCH EVERYONE FOR DOING THE SURVEYS! I've received over 600 responses! (500 today alone, thanks to being featured on the front page. Thanks Brian!) Next time I'll give a breakdown of the responses and what it will mean for the PSDR moving forward.

I'm trying to work out the details of making the PortableSDR available, but there are some things I need to figure out. Please please take a moment to fill out this survey so I can plan things out appropriately. It should only take a minute. Thank you so much!

I spent the last few days modifying the design of the case to simplify it (7 screws instead of 21, for example) and to make it millable. I had some great help from my friend Jacob, thanks Jacob! He also suggested a countersunk front cover and I think it's going to look awesome! I spent pretty much all of Saturday at work, generating toolpaths and "borrowing" the milling machine. I made a few mistakes, learned a bunch of stuff. It was pretty fun! I'm getting better! I'm probably going to sandblast it when it's done (you can see I need to hand finish a little bit, particular around the paddle area.) so it will have a soft, frosted look. At least for now. I might paint it after that. We'll see.

I also want to share some small miracles. Those of you who are offended and/or not interested in religious things can skip the rest.

Let me first say how blown away, honored, and delighted I am to be included in the final round of judging! The enthusiastic responses I've gotten from everyone have helped keep me motivated through the long hours of design and programming (honestly, this would have been a year long project or more otherwise). Thanks to everyone for your support! I've loved reading everyone's comments here on my project blog, on the final-five announcement page, youtube, and reddit.

Now then! Where were we. It seems like many people have been anxious to see transmit support working. I realized that some of the other features I'm excited about, like the Vector Network Analyzer, require the PSDR to generate signals, and of course, I want to see if I can talk to people with it! So, as you saw in the last video, I got transmit support started, but I was a little disappointed that the power output was so low (I mean, I knew it would be low but...)

So, I decided to try my hand at putting together an amplifier to go in the PSDR2's amp board socket (those five holes in the upper left), and this is the result. PCBs should get here next week, hopefully in time for the final judging. If it works the way I think it will, it should get us somewhere close to 100-200mW. Still not a lot, but enough to get a signal out, and maybe drive another amplification stage in the future.

It was fun to design. I'm trying some weird stuff here, for example, the two MMIC amplifiers are biased like a diode or transistor (well, that's what they are), where current is more important than voltage. Also, they like to be driven around 5-6v. So I needed a boost converter, ideally with a constant current output. Well. they make LED drivers that do exactly that. So that's what will be powering this little amp.

I'm actually not totally confident it will work on the first try, but it will be a learning experience either way.

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This project has my mouth watering. I would really love to have one of these and it would perhaps become my main rig. I hope one day that it will become affordable for me as I am disabled and on a fixed income. In the mean time, I will save my pennies and hope to one day purchase one of these.

I wish to thank you for all of the hard work, skill and love you have put into this project! I know that you are an inspiration to others that are or are maybe considering creating great things like the PSDR!

Michael, this project is inspired! I NEED this radio. Well, I REALLY WANT this radio! I'm a new HAM and have very little experience working with electronics. How difficult would it be to learn how to solder in order to assemble a parts-only kit? Is that the kind of thing that takes a long time to develop the skill? I guess I'm saying that if it isn't too difficult to learn, and that would get me a radio faster, I'd be willing to learn!
Also, I voted for an aluminum case, but would be willing to take a plastic case if the metal one was a cost-deal-breaker.
In the survey it asked if a non-working speaker would be acceptable. Does the unit have a headphone jack?
Please, please, please be sure to notify me when even the most basic kits are available!
Thank you.

This is certainly a game-changer for the Art of Amateur Radio! Something like this is what the average operator can make use of having limited antenna space for small dwellings and an integrated, stand-alone, ability without a PC to operate Weak Signal modes world-wide. Will be great to use in antenna experimentation and optimization. Getting an efficient antenna setup is key to QRP operation and the built-in VNA is just what is needed! Eventual WiFi and Bluetooth interface option, if possible, would also be cool! Hope there will be supporting Apps for the unit to follow. Great Work, Michael!

Michael, love your project, wish I could help out in some way but I don't really undrstand a lot of what's discussed, and couldn't donate a nickle but I can offer my encoutagement. I have no idea what this will eventually sell for but I want two for my sailboat, one to use and one to put in my emergency bag.. Good Luck!!

Like the aproach angle on this small SDR. Kind of a nice product. Can't wait for the public models. Kind of using it as a DAP with a small antenna and a couple of earplugs that do not draw a lot of power, like 20mW or so. Have a MobiBlu DAP-1900 that only needs charging every 153 hours on one Lithium battery. Just the tought of walking around with a PSDR in my pocket during outdoor escursions sounds great. 73' Ron - ON2RON

Hi Michael. Just back from Hackaday Price event. Congrats for 3rd place. I really would have seen Portable SDR number 1. For me it is. Keep on hacking. I'm sure we will see exiting things when Portable SDR get's into the hand of some Hacker OMs.

Hi Michael. It looks like your Portable SDR is getting attention outside of HAD: http://qrznow.com/portable-sdr/I suspect you already know, but I figured I'd share the link for the benefit of others here.

Hi Michael! First, congratulation for you great project and your acheivement! I beleive that a new step of DXing and exploring mobile SDR possibilities has been reached thanks to this project!Me and my radio amateur friends will be gad to assemble this kit if all the components and parts are available. I am not a great electronician but I'll really be happy and glade to build one of your kit so please let me know when and how I'll be able to order one full kit!
Cheers!

Considering power (future version); the end power amplifier is the most hungry unit , focusing on that, I would use a higher voltage battery and down-DC-convert for the low-power parts. Using a higher voltage with an amplifier makes it more efficient . Also it would be interesting to investigate dpwm (digital pulse width modulation) where you can go to 90% efficiency , thus doing away with most of the analog TX stuff.
pe1bfe

Thanks for the suggestion. I'll consider it. I wonder about finding higher voltage packs that are small enough. (Also, am I the only one that has found it hard to find a multi-cell balancing LiPo charge IC?)

The other thing, and maybe this is just how I operate, I spend WAY more time listening than transmitting, so most of my optimizations would probably focus on getting non-transmitting consumption down. Anyway, I am still working on all that.

I definitely like the idea of a PWM amp, but.... since I am pretty new to amplifier design, I think I'll have to start with a boring, inefficient linear amp. I would be very open to amp design assistance btw!

I'm an RC plane guy and a HAM. I was just reading that if you are discharging the LiPo at 1 to 2 C rates then you don't really need to balance the cells. It's when you start doing 20C discharge rates that it matters. Might make your charging circuit a lot simpler if it's just not an issue.

I read this in a comment from the guy that sells LiPo battery replacements for FT-817nd transceivers. They are 5 Watt radios. Something to explore anyway.

I hope you don't take this the wrong way, but you seem to have spent a great deal of effort on the computing side, but you cannot transmit. Here is my suggestion. Rather trying to build an super-duper open source SDR radio, why not use one of very many cheap android and windows phones as your computing platform. That way you could simplify the design and then all they would have to do is pair the RADIO with a suitable smartphone or table and the software can be downloaded from app store? in the UK, you can buy a quad-core smartphone with multiple cameras, wifi, bluetooth gps etc etc for under £50, say under $100 dollars US.

The would help keep the cost down as you would not to price in an ARM processor, colour display etc. I would keep the GPS RX as this makes a great frequency standard. It would be like using websdr.org or similar.

By doing this you do one as self contain radio, or as a raspberry PI shield. If it were a black brick, paired with smartphone you have the benefit of more processing power and storage, without adding to cost (reducing it, in fact!) And, remember, smartphones have cameras, so SSTV and FAX are a possibility, and even fast scan TV via transverter. Don't forget augmented reality / DX cluster etc etc

Satellite operation would probably be easier as the smartphone's magnetometer would help make sure that the antenna(s) are pointing in the right direction.

Thanks for the feedback. I mentioned below most of my reasoning for going the route I did (mostly to keep it all in one) but there are other issues to using a smartphone too, like managing the connection between the two devices, bandwidth, non-realtime OS. On the other hand, some things would be SO much easier.

I've actually done work designing external IO hardware for android devices (if any of you hop in a taxi in Las Vegas, that advertizing thing on the ceiling? I made that) and it's okay. I'm not opposed to trying something like that in the future... We'll see.

It might not affect cost as much as you might think though. It will absolutely still need some sort of microcontroller (the chip in the PSDR2 has 100 lines and I used every single one!) I'd be able to use a less powerful chip if the phone did the DSP and display stuff, but the microcontroller only makes up about $20 of the cost of the PSDR and the display only adds about another $5.

I love the project I just wanted to touch on the licensing. If you don't care what happens to the code IE if it is sold when changed or just given away go with the MIT licences if you want to make it free for every one at all times go with the GPL licence. It really comes down to how you want to see the software evolve. I personally like the idea of GPL licence it is more complicated but it keeps all versions open and free to the public at all times. Please note that I am not a lawyer and this not meant to be taken as legal advice I would recommend sitting down with a copyright lawyer if you can.

Thank you for that clarification! I think I agree with you that I'd like future and derivative works to be open and contribute to the success of all versions. So maybe GPL it is? I don't have any copyright lawyers handy...

Some people dislike copyleft licenses such as GPL because of the requirement to release all derivatives. Just something to keep in mind. Of course, other people like them for the same reason. Also take a look at the Artistic License for a different take on copyleft.

You might consider adding the "real" transmitter parts (5w amp, antenna tuner, BNC connector, additional battery) in another identical enclosure that attaches to the bottom of the main pSdr unit. Make it optional. That way it can be designed more freely, be bought later by those who might be short on $$, and remain optional for those who don't want it. KD1JV uses BS170's as final drive transistors in many of his CW designs, and the good ol IRF510 is a classic low power final choice. There may be more efficient choices out there these days though! thanks for a greatroject!
73 de Steve, W2STV

I have thought about a backpack for the PSDR. Someone else mentioned a dock as well. One of my primary goals with the PSDR was that it be a single unit. So much of portable ham operating seems to be, for example, an FT817 + battery + tuner + key + microphone + antenna. If I can, I really want to get it all in one piece (if only I could fit the antenna inside. Fractals!). That said, I don't know if it's possible to make it small enough, particularly if I include something like a tuner. Actually, that's what the VNA is supposed to be for, so you can either adjust your antenna in the field, or identify frequencies that your antenna is already matched for and use those. We'll see. Even if it isn't really what I had in mind, I might at least put features on the case that a backpack or dock could connect to... We'll see. It just occurred to me, someday there might be 3rd party accessories for the PSDR. That would feel really weird.

Thanks for the suggestions on drive transistors, I'll look into those. Take care!

No doubt you will get lots of suggestions of different features to be added. A very good way to determining if a person has been operating portable or not is if they ask for a tuner to be included in the box. Anyone who has been working portable a couple of times know that a separate tuner is way better, particularly if you are using an EFHW, so don´t fall for that! Ever!
SM6EQO

I would stay on your course. Your basic premise works for me. I like the single unit design. Your circuit layout indicates charging in the field, and I assume you could use a solar cell setup as well. The ability to read SWR from the unit is also a plus for those who carry pre built antennas to the field.

Bluetooth it!
You could reduce cost, and power needs (more available for TX?) if this was controlled via a Bluetooth smartphone. The on-board LCD is GREAT, but now that smartphones are ubiquitous - it may be worth thinking about as an optional control method. In other words you could buy the standalone LCD version or the Bluetooth version.

I've thought about bluetooth. As I mentioned to Steve Maietta above, I really wanted the PSDR to stand alone, so that model is the priority. But I have considered adding bluetooth, like you suggest, so that phones (or keyboards) can connect to it, particularly to make digital modes easier.

BUT! It had also occurred to me to make a completely blackbox model. You screw it onto an antenna and throw the whole thing in a tree, then operate it with your phone. No coax needed! I actually rather like that idea, I might pursue it when the PSDR is a little further along. (I'm also pondering a car version, but don't tell anybody)